Prof. James F. Scott, FRS of the Cavendish Laboratory, Cambridge UK, has published advice (in the Journal of Physics: Condensed Matter) for the attention of fellow ferroic researchers.
“If your ‘hysteresis loops’ look like figure 1(a), please do not publish them. Publish data that are saturated and have a region in Q versus V that is concave. Bananas are not ferroelectric, and it is easy to be misled by closed Q (V) loops.”
“We show that ordinary bananas exhibit closed loops of switched charge versus applied voltage that are nearly identical to those misinterpreted as ferroelectric hysteresis loops in crystals.”
See: ‘Ferroelectrics go bananas’ J. Phys.: Condens. Matter, 20 (2008) 021001.